Tiffany &amp; Co sued Costco Wholesale Corp on Thursday to stop the largest U.S. warehouse club chain from selling what it called counterfeit diamond engagement rings bearing the luxury retailer's name.

Oracle, Discover and Tiffany are all expected to report year-over-year growth for their most recent quarters this week. Meanwhile, many will be looking for an updated snapshot of the housing market, with three sets of real-estate data coming out.

The Japanese are the world's most voracious consumers of luxury goods, from Louis Vuitton handbags to Cartier jewelry to Hermes high fashion. So purveyors of those luxury goods are justifiably worried about the effect of the Japanese earthquake and tsunami on their bottom lines.

Spending for the lovers' holiday this year is expected to climb 5.8% over 2009, and that spells opportunity for investors. Here are some greeting card, candy, jewelry, flower and restaurant stocks that could get a lift from sweethearts looking for that special something.

Valentine's Day sales should thrill the hearts of retailers this year: Spending for the day is forecast to top $18.6 billion, a 5.8% jump in spending over 2010. That amounts to about $125 per person taking part in the holiday for lovers.

Recognizing that even the well-heeled have money problems these days and trying to expand their customer base, many luxury-goods sellers now have something for (almost) everyone. Here's a rundown of some less-pricey goodies you can get at the toniest shops in town.

Want to be an extra-generous Santa in 2010? Try buying the most expensive item at each of 12 popular U.S. retailers. According to an unscientific survey by 24/7 Wall St, that would set you back nearly $15 million (thanks mainly to a visit to Tiffany).

Luxury retailers tend to be early cycle stocks: They move in advance of other sectors. Shares in Tiffany, Coach and Polo Ralph Lauren have been been crushing the broader market for a while. But will they continue? Do their stocks make good buys? Watch Face-Off.